<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #container {
        padding-left: 200px;
        padding-right: 150px;
        overflow: auto;
        }
        #container p {
        float: left;
        }
        .center {
        width: 100%;
        background-color: lightcoral;
        }
        .left {
        width: 200px;
        position: relative;
        left: -200px;
        margin-left: -100%;
        background-color: lightcyan;
        }
        .right {
        width: 150px;
        margin-right: -150px;
        background-color: lightgreen;
        }
        .clearfix:after {
        content: "";
        display: table;
        clear: both;
        }
    </style>
</head>
<body>
    <div id="container" class="clearfix">
        <p class="center">我是中间</p>
        <p class="left">我是左边</p>
        <p class="right">我是右边</p>
      </div>
</body>
</html>